Protective device and slope stabilization

ABSTRACT

A protective device, in particular an erosion protection device and/or a drainage device configured as a geotextile, includes a mat element, which is at least intended to be spread flat over a surface to be protected and which is formed at least to a large extent from a three-dimensional, nonwoven-like, and tangled nonwoven-like, composite with a multiplicity of fibres.

CROSS-REFERENCE TO FOREIGN PRIORITY APPLICATION

The present application claims the benefit under 35 U.S.C. §§ 119(b), 119(e), 120, and/or 365(c) of PCT/EP2021/052706 filed Feb. 4, 2021, which claims priority to Application DE 102020103812.7 filed Feb. 13, 2020.

FIELD OF THE INVENTION

The invention relates to a protective device relates to an erosion protection device or drainage device, in particular, to a protection device having a mat element formed as a composite of biodegradable plastic fibres.

BACKGROUND OF THE INVENTION

A protective device with a mat element, which is at least intended to be spread flat over a surface to be protected and which is formed at least to a large extent from a non-woven composite with a plurality of fibres, has already been proposed.

The task of the invention is in particular to provide a such defined device with advantageous protective properties, which is in particular at the same time particularly environmentally compatible. According to the invention, the task is solved by the features disclosed herein, while advantageous embodiments and further embodiments of the invention can be taken from the further features disclosed.

SUMMARY OF THE INVENTION

The invention is based on a protective device, in particular an erosion protection device and/or a drainage device, preferably a geotextile, with a mat element which is at least intended to be spread flat over a surface to be protected and which is formed at least to a large extent from a, in particular three-dimensional, nonwoven-like, in particular tangled nonwoven-like, composite with a multiplicity of fibres.

It is proposed that the fibres are designed as biodegradable plastic fibres. In this way, advantageous protective properties in particular can be achieved with a high level of environmental compatibility at the same time. Advantageously, the protective device weathers free of environmentally harmful and/or unnatural residues, in particular free of plastic residues, in particular macro-, micro- and/or nanoplastic residues, which in particular are not biodegradable even on large time scales, and/or free of (heavy-) metallic residues. Thus, a good environmental compatibility can advantageously be achieved, whereby a particularly good suitability for use in ecologically sensitive regions can advantageously be achieved.

In addition, a high biocompatibility can advantageously be achieved, in particular with the vegetation and/or fauna surrounding the protective device. For example, damage to living organisms that incorporate fibres of the protective device and/or an accumulation of microplastics in the food chain can be advantageously kept low. Advantageously, the mat element formed from the biodegradable plastic fibres has a longer service life under the same weathering conditions than erosion protection mats made from biodegradable natural materials such as coconut fibres, reed fibres, jute fibres or the like. As a result, erosion protection can advantageously be guaranteed over a period of years (instead of months) while still ensuring a high level of environmental compatibility

Advantageously, the mat element formed from the biodegradable plastic fibres has a comparable service life and/or a comparable durability (tear resistance, etc.) as currently used erosion protection mats made of polypropylene (PP), which forms micro- and nanoplastic particles when weathered. In particular, it is conceivable that the mat element has further components, in particular fibres, in particular that further components, in particular fibres, are added to the composite, but preferably the mat element is predominantly and preferably entirely formed from the biodegradable plastic fibres.

The protective device is intended in particular for protection, in particular erosion protection, of a sloping terrain, in particular for slope and/or hillside protection, for example in civil engineering, hydraulic engineering and/or road construction and/or preferably in the context of geotechnical securing structures. In particular, the protective device is intended for use in the context of biological engineering construction measures. Alternatively or additionally, the protective device is provided for a drainage of a surface, for example a floor, in particular a floor of a structure, or a roof, in particular a flat roof of a structure. In this case, the mat element forms a drainage mat. Alternatively or additionally, the protective device may be provided for use in agriculture, for example for the protection of fruits. For example, in strawberry cultivation, the protective device can be placed under the strawberries ripening on the plant as an alternative to wood wool or the like, so that they do not come into contact with the soil.

Alternatively or additionally, the protective device is intended to facilitate and/or enable re-vegetation and/or re-vegetation of a terrain, in particular a sloping terrain. In particular, the protective device, preferably at least the biodegradable plastic fibres of the protective device, is intended to be completely disappeared, in particular rotted, after a period of time which can be predetermined, in particular depending on a design of the plastic fibres (thickness, length, shape, number, etc.) and/or on a design of the composite (fibre density, type and/or degree of entanglement of the fibres, etc.), for example after one, two, three or more vegetation periods. For example, a protective device provided for rapid re-vegetation of a site with a fertile topsoil layer has a comparatively fast-rotting mat element which is already almost completely decomposed, in particular after just one or two growing seasons. Alternatively, for example, a protective device provided for a terrain with barren, infertile, e.g. stony or very steeply sloping, soils has a comparatively slow rotting design and decomposes only after several, for example four, five, six or more growing periods. Advantageously, a rotting period of the plastic fibres can be adjusted by means of a setting of the composition of the fleece-like composite and/or can be adapted to expected weather conditions. The protective device, in particular the geotextile, is designed in particular as an embankment mat and/or as a claw mat.

A “geotextile” is to be understood in particular as a flat or three-dimensional textile which is permeable to water and which is used as a building material in the field of civil engineering, water engineering and traffic route construction and/or for geotechnical securing work. Preferably, a geotextile is intended for separation, drainage, filtering, reinforcement, protection, packaging and/or erosion control. In particular, the geotextile is in the form of a non-woven geotextile. By “intended” is meant in particular to be specially programmed, designed and/or equipped. By the fact that an object is intended to perform a specific function, it should be understood in particular that the object fulfils and/or performs this specific function in at least one application and/or operating state.

The term “plastic fibre” shall be understood in particular to mean a fibre consisting of macromolecules, the main and/or basic chemical constituent of which is at least one synthetically or semi-synthetically produced polymer with organic groups and/or regenerated cellulose. Preferably, the plastic fibre is a polymer fibre, preferably a synthetic fibre, and/or a regenerated fibre, preferably a viscose fibre. In particular, a plastic fibre forms a staple fibre, which is preferably extruded via a melt spinning process using screen plates. Alternatively, however, it is also conceivable that the plastic fibre forms an extruded monofilament. Particularly in comparison to geotextiles made of natural fibres, for example jute, reed and/or coconut fibres, a speed of biological decomposition can be advantageously slowed down. Plastic fibres are advantageously less susceptible to infestation with mould fungi. Advantageously, the plastic fibres have a low absorbency for water, which advantageously further reduces a risk of infestation with moulds. In particular, the plastic fibres have a round cross-section, an oval cross-section, a trilobal cross-section and/or an angular cross-section. In particular, at least some of the plastic fibres are formed as staple fibres, preferably all plastic fibres are formed as staple fibres. Alternatively or additionally, in particular at least some of the plastic fibres can be formed as continuous fibres.

The fact that the plastic fibres form a “three-dimensional composite” is to be understood in particular as meaning that individual plastic fibres of the plurality of plastic fibres are/can be aligned in different directions encompassing all three spatial directions and/or that the plastic fibres have in particular at least partial and/or sectional alignment in a direction perpendicular to the planar propagation direction of the protective device. In particular, different partial sections of a plastic fibre can be oriented in at least two different spatial directions, preferably in at least three different spatial directions. In particular, the entire mat element is formed three-dimensionally. In particular, the mat element is a two-dimensionally spreadable and three-dimensional fleece-like textile. Preferably, due to the three-dimensional structuring, the protective device has an extension perpendicular to the planar spreading direction, in particular a thickness, which is greater than 4 times, preferably 6 times, advantageously 8 times, particularly advantageously 10 times, preferably 20 times and particularly preferably less than 100 times a mean diameter of the plastic fibres, in particular a mean diameter of the plastic fibres of a fibre type with the largest diameter of all fibre types. In particular, the mat element and/or the composite has cavities. In particular, the protective device, preferably the mat element and/or the composite, is not opaque. Alternatively, however, it is also conceivable that the mat element is opaque. Alternatively, it is also conceivable that the mat element is formed to be at least substantially flat, in particular two-dimensionally extended. In particular, the mat element is formed free of a superstructure, in particular a pyramid-like superstructure. Preferably, the surfaces of the mat element, in particular of the composite, are at least substantially flat and/or free of periodic, grid-like or randomly arranged protrusions. Preferably, the mat element is water-permeable. In particular, individual plastic fibres are formed as solid bodies, which are preferably free of further materials other than the biodegradable plastic(s), possible additives for controlling biodegradability and/or possible dyes. Alternatively, at least part of the plastic fibres may form a core-sheath structure in which a core formed of at least one deviating material, for example a natural fibre such as a coconut or jute fibre, is surrounded by a sheath of biodegradable plastic. By means of such a core-sheath structure, an absorbency for liquids of the natural fibres can advantageously be controlled. A “composite with a plurality of fibres” is to be understood in particular as a connection of parts, i.e. in the present case predominantly fibres, to form a unit, i.e. in the present case the mat element.

The three-dimensionality of the composite is intended in particular to ensure that plant seeds get caught in the structuring during insemination and thus remain in place even on a sloping terrain and, in particular, are not washed away by rain or the like. In addition, seeds caught in the three-dimensional composite are advantageously exposed to good germination conditions, in particular by being protected from conditions that are too moist and/or too dry for successful germination, for example by being able to keep the seeds away from excessively moist ground such as puddles (prevents rotting) and at the same time being supplied with sufficient moisture by dew formation on the large surfaces of the plastic fibres (favours germination). In addition, the three-dimensionality of the composite advantageously supports bed stabilization, in particular because the three-dimensionality gives the mat element an advantageously high sliding friction.

The fact that at least the plastic fibres are biodegradable is to be understood in particular as meaning that the plastic fibres are made of a biodegradable plastic. Preferably, all plastic fibres of the mat element and/or at least of the composite are biodegradable. In particular, the biodegradable plastic fibres are free of oxo-degradable plastics. In particular, the biodegradable plastic fibres are free from polyethylene, polyvinyl chloride, polyethylene terephthalate and/or polypropylene.

The term “biodegradable” is intended to mean in particular biodegradable and/or biodegradable. In particular, a biodegradable plastic fibre is intended to decompose to a large extent to carbon dioxide (CO₂), water (H₂O) and screenable residues of low, preferably disappearing, ecotoxicity within an ecologically compatible period of time. Preferably, at least 90% of the organic fractions of the plastic fibre decompose into CO₂ and/or H₂O within the ecologically compatible time period. In particular, decomposition of the biodegradable plastic fibres takes place at least to a large extent by microorganisms and/or by water, or with the aid of water. In particular, a decomposition of the biodegradable plastic fibre leads to a preferably complete conversion of the biodegradable plastic fibre to CO₂, H₂O and/or biomass. Preferably, 90% of the remainder of the plastic fibre that has not been converted to CO₂ can be screened through a sieve with a maximum sieve hole diameter of 2 mm after the ecologically compatible period has elapsed. The ecologically compatible period is in particular at least one year, preferably at least 1.5 years, advantageously at least 2 years, preferably at least 3 years and particularly preferably at least 5 years. Furthermore, the ecologically compatible period is in particular at most 50 years, preferably at most 35 years, advantageously at most 25 years, particularly advantageously at most 15 years, preferably at most 10 years and particularly preferably 5 years. In particular, the residues of the plastic fibre do not have any concentrations of the elements zinc, copper, nickel, cadmium, lead, mercury, chromium, molybdenum, selenium, arsenic and fluorine or only low concentrations of said elements which do not exceed the limit values specified in the standard DIN EN 13432:2000. Preferably, residues of the plastic fibre, in particular in contrast to residues of polyvinyl chloride, do not have concentrations of hydrogen chloride. In particular, the plastic fibres do not produce any negative effects on a natural composting process. In particular, test fibres identical to the plastic fibres meet at least the aforementioned conditions of ecotoxicity, sievability and conversion to CO₂ within the ecologically compatible period when the test fibres are subjected to a test trial under the composting conditions specified in the standard DIN EN ISO 14855:2004-10. Preferably, the biodegradable plastic fibres are made at least to a large extent, preferably completely, from bio-based, in particular non-fossil, raw materials. In particular, the biodegradable plastic fibres are completely metabolisable by organisms, in particular microorganisms, to biomass. Advantageously, a service life of the mat element depends on a presence and/or concentration of microorganisms. Thus, it can be advantageously achieved that weathering at an installation site with a lot of vegetation, i.e. many microorganisms, is significantly faster than at a site with little vegetation and few microorganisms (deserts, etc.). At sites with vegetation, after the biological decomposition of the mat element, the vegetation takes over the protective effect, especially the erosion effect, whereas at a site with little vegetation, the protective effect can advantageously be generated by the mat element for a long time.

The term “non-woven composite” is intended to mean in particular a composite forming a non-woven fabric. In particular, the non-woven composite is to be understood as an assembly of fibres of limited length, of filaments and/or of cut yarns which have been joined together in any way to form a non-woven (a layer of fibres) and bonded together in any way, excluding the interlacing and/or intertwining of yarns as occurs in weaving, knitting, lace-making, braiding and in the manufacture of tufted products. In particular, the non-woven composite forms a non-woven (unwoven), non-knitted (unknitted), non-knitted (unknitted), non-braided (unbraided) structure. In particular, a nonwoven fabric forms a flexible (easily bendable) textile structure, the main structural elements of which are fibres. In particular, a nonwoven fabric has a comparatively small thickness compared to its length and width. In particular, the nonwoven fabric is formed differently from film-like structures. In particular, the nonwoven fabric is formed differently from fibre-reinforced plastic structures. In particular, the nonwoven fabric is formed differently from papers. In particular, a nonwoven fabric may be formed as a felt, in particular as a needle felt. Preferably, the term nonwoven shall be understood in the context of this document according to the definition in the standard DIN EN ISO 9092:2012-01, preferably according to the definition in the standard DIN EN ISO 9092:2019-08. A “tangled nonwoven composite” is to be understood in particular as a nonwoven composite which forms a tangled nonwoven, in particular a tangled layer nonwoven. In particular, the tangled nonwoven is formed as an anisotropic nonwoven, preferably a carded nonwoven, which in particular has a preferred fibre orientation. In particular, the carded nonwoven consists at least to a large extent of fibres which have a matching preferred direction, in particular preferred surface direction and/or preferred spatial direction. Alternatively, it is conceivable that the tangled nonwoven fabric is formed as an isotropic nonwoven fabric, which is preferably free of a preferred fibre orientation. In this case, the tangled nonwoven would consist at least to a large extent, preferably completely, of fibres which occupy any desired surface direction, preferably any desired spatial direction. In addition, the entangled nonwoven would consist at least to a large extent, preferably completely, of fibres which are relatively equally distributed in all directions of the nonwoven, preferably in any surface direction, preferably in all spatial directions. In particular, the nonwoven fabric, preferably the entangled layer nonwoven fabric, can be formed, in particular manufactured, as a needlefelt nonwoven fabric.

If the fibres comprise a biodegradable polylactide plastic (polylactic acid, PLA) or are preferably formed and/or manufactured from the biodegradable PLA plastic, a protective device with advantageous protective properties can in particular be achieved with a high degree of environmental compatibility at the same time. Advantageously, the PLA plastic has an at least substantially neutral carbon footprint, since it can advantageously be obtained from renewable raw materials, whereby in particular negative effects on the climate and thus on the frequency of weather extremes can be avoided. Furthermore, fibres made of PLA plastic advantageously exhibit a particularly stable, especially constant, tensile strength even after significant weathering. In addition, fibres made of PLA plastic have an advantageously high UV resistance, in particular even without added UV stabilisers. As a result, a longer service life can advantageously be achieved than with natural fibres such as coco, reed or jute fibres. Advantageously, a service life comparable to that of PP fibres can be achieved with advantageous additional biodegradability. Fibres made of PLA plastic are also advantageously more hydrophobic, at least compared to PP fibres. Fibres made of PLA plastic are also advantageously spinnable and/or extrudable. Fibres made of PLA plastic are furthermore advantageously flame retardant. Preferably, all plastic fibres are formed at least in part from the PLA plastic. Preferably, all plastic fibres are formed entirely from the PLA plastic.

If, in addition, at least a substantial part of all fibres of the composite, preferably all fibres of the composite, are stretched, in particular pre-stretched, the protective properties of the protective device can advantageously be further improved. In addition, a durability, in particular service life, can thereby be advantageously increased. Furthermore, a tensile strength of the fibres can thereby advantageously be increased. The expression “pre-stretched” is intended to be understood in particular before insertion into the non-woven fabric and/or before joining to form the non-woven fabric. The expression “a substantial portion” of the fibres is intended to mean in particular at least 20%, preferably at least 30%, advantageously at least 40%, preferably at least 50% and particularly preferably at least a majority of all the fibres of the composite. By “a majority” is meant in particular 51%, preferably 66%, advantageously 75%, particularly advantageously 85% and preferably 95%. Particularly preferably, all fibres of the composite are stretched, in particular pre-stretched. In particular, stretching leads to a change in the material properties of the fibre, inter alia by partial crystallisation, in particular at least by an increase in a partially crystallised fraction, of the originally predominantly amorphous PLA plastic. In particular, by forming the mat element as a nonwoven and/or by pre-stretching the fibres, it is advantageously possible to dispense with the use of other types of plastics in addition to PLA, while at the same time achieving a sufficiently high stability and/or usability, in particular in comparison with previous mat elements. Nevertheless, it is conceivable that at least a part of all fibres may contain another biocompatible and/or biodegradable plastic, such as a plastic from the group of polyhydroxyalkanoates (PHA group), such as polyhydroxybutyric acid (PHBV), a polycaprolactone (PCL) plastic, a polybutylene succinate (PBS) plastic, a polybutylene adipate terephthalate (PBAT) plastic and/or a blend, in particular a spinnable blend, of at least two of the aforementioned biodegradable plastics. For further properties of the aforementioned plastics, reference is made in particular to the German patent application with application number DE 10 2018 123 477.5.

Furthermore, if at least a substantial part of all fibres of the composite, preferably all fibres of the composite, are pre-formed and/or pre-entangled, advantageously the protective properties of the protective device can be further improved. Advantageously, an improved cohesion of the composite can be achieved, in particular by higher frictional forces and/or a higher degree of entanglement. Advantageously, an increased tensile strength of the mat element can thus be achieved. In particular, pre-deformed and/or pre-corrugated fibres are non-straight in an initial state, preferably before being added to the composite or before being joined to the composite. In particular, the pre-deformed and/or pre-corrugated fibres in the initial state are each bent several times, preferably in different directions. However, it is also conceivable that the fibres are not pre-shaped or pre-corrugated.

It is further proposed that the mat element has a mass per unit area (grammage) of less than 400 g/m², preferably of less than 350 g/m², preferably of less than 300 g/m², in particular with a thickness of the mat element of at least 0.5 cm, preferably at least 1 cm, preferably at least 2 cm, preferably at least 3 cm and particularly preferably at least 4 cm. Advantageously, this allows a weight of the protective device to be kept low. Advantageously, this can facilitate assembly, in particular in impassable and/or sloping terrain, whereby in particular a workload for assembly personnel can be substantially reduced and/or safety for assembly personnel can be substantially increased. In addition, material costs can be kept advantageously low. Advantageously, an increase in the strength and/or stability of the mat element can be achieved by stretching and/or preforming the fibres, so that a weight per unit area can be reduced, in particular compared to a mat element with non-stretched and/or non-preformed fibres, without resulting in a reduction in stability and/or strength. In particular, it is also conceivable that the mat element has a weight per unit area of less than 499 g/m².

It is further proposed that at least a substantial portion of all fibres, preferably all fibres of the composite, have a specific gravity, in particular a density, which is greater than the specific gravity, in particular the density, of water, in particular under standard conditions. Advantageously, this can further increase a protective effect, preferably an erosion protection effect, of the protective device. In particular, a contact of the protective mat with the surface to be protected can advantageously be improved. Advantageously, it can be achieved that even during heavy rainfall and/or flooding the mat element does not float, which is for example in contrast to PP fibres, which have a lower specific weight than water and would therefore float. In particular, the specific weight is intended to mean a weight which preferably describes a ratio of a weight force of a body, in particular a fibre, to a volume of the body, in particular the fibre. In particular, the SI unit Nm⁻³ is assigned to the specific weight. In particular, the specific gravity of one of the PLA fibres is about 12.2 kNm⁻³. In particular, the specific gravity of water is about 9.8 kNm⁻³. In particular, the specific gravity of one of the PP fibres is about 9.3 kNm⁻³. In particular, at least a substantial part of all fibres, preferably all fibres of the composite, has a specific gravity, in particular a density, which is greater than the specific gravity, in particular the density, of PP fibres, in particular under standard conditions. Standard conditions” should be understood to mean in particular normal physical conditions (temperature=273.15 K, pressure=1.01325 bar).

In addition, it is proposed that the fibres, in particular at least one type of fibre of the fibres, have an average length of at most 20 cm, preferably at most 15 cm and preferably at most 10 cm. In this way, a particularly advantageous balance can be achieved between the highest possible tensile strength of the mat element and a simplicity and/or efficiency of the manufacturing process of the fibres and/or of the composite with the fibres. In particular, the average length of the fibres is at most 30 times, preferably at most 20 times and preferably 15 times an average thickness of the mat element. In particular, the average length of the fibres is at least 2 cm, preferably at least 3 cm, preferably at least 4 cm and particularly preferably at least 6 cm.

It is further proposed that at least a substantial part of all fibres of the composite, preferably all fibres of the composite, have colour pigments, in particular specifically admixed colour pigments. The colour pigments are, in particular completely, biocompatible and/or biodegradable. In this way, a particularly high level of environmental compatibility can advantageously be achieved, in particular in that as many as possible, advantageously all components of the protective device, in particular of the mat element, are completely biocompatible and/or biodegradable. Preferably, the colour pigments are natural pigments. Alternatively, however, the colour pigments may also be formed as biocompatible and/or biodegradable synthetic pigments. In particular, the colour pigments are formed as an integral part of the fibres. In particular, the colour pigments are added to the PLA plastic during the production of the fibres. Alternatively, however, it is also conceivable that at least a major part of the fibres is covered on one surface by a colour layer comprising the colour pigments or by a colour layer consisting of the colour pigments. In this case, the fibres or at least a part of all fibres are painted and/or coated. Preferably, the fibres are pre-coloured, in particular pre-painted and/or pre-coated, in particular before being added to the composite and/or before being joined to the composite. Preferably, the colour pigments impart to the fibres a colour close to nature, which in particular occurs frequently in nature, such as for example a brown tone (earth), a green tone (vegetation), a grey tone (rock), a yellow tone (sand) and/or a mixture thereof. Advantageously, a colour of the mat element can be flexibly adapted to a colour of an environment of an installation site.

It is also proposed that at least a substantial part of all fibres, in particular all fibres forming the composite, have a diameter of less than 2 mm, preferably less than 1 mm. Advantageously, this allows the weight of the protective device to be kept low. Advantageously, assembly can thereby be facilitated, in particular in impassable and/or sloping terrain, whereby in particular a workload for an assembly personnel can be substantially reduced and/or safety for the assembly personnel can be substantially increased. Advantageously, an increase in the strength and/or stability of the mat element can be achieved by stretching and/or preforming the fibres, so that a diameter of the fibres can be reduced, in particular compared to a mat element with non-stretched and/or non-preformed fibres, without resulting in a reduction in stability and/or strength. In addition, an advantageously high flexibility of the mat element can be achieved, which can thereby advantageously adapt particularly well to a topography of a surface to be protected. In particular, at least a substantial part of all the fibres, preferably all the fibres forming the composite, has a fineness, in particular an average fineness, of less than 350 dtex, preferably less than 300 dtex, advantageously less than 250 dtex, particularly advantageously less than 200 dtex, preferably less than 150 dtex and particularly preferably less than 100 dtex. It is also conceivable that at least some of the fibres, for example fibres of a particular fibre type, have a fineness, in particular an average fineness, of less than 50 dtex, preferably less than 31 dtex.

In addition, it is proposed that the fibres comprise at least a plurality of fibres of a first fibre type and at least a plurality of fibres of a second fibre type, wherein the fibres of the first fibre type and the fibres of the second fibre type differ substantially from each other. In particular, advantageous protective properties can be achieved while at the same time maintaining a high level of environmental compatibility. Advantageously, an adjustment of physical properties (basis weight, colouring, tensile strength, etc.) of the mat element can be achieved by mixing the fibre types. In particular, it is conceivable that the composite comprises at least one or more further fibre types, each comprising a plurality of fibres, each of which differs substantially from the fibres of other fibre types. The expression “differ substantially” is intended to mean in particular that at least one property, in particular a physical or chemical property, differs between the fibre types in a way that is at least measurable and/or at least visible to the naked eye, preferably by at least 5%, preferably by at least 10%, preferably by at least 25% and particularly preferably by at least 50%.

It is further proposed that the fibres of the first fibre type and the fibres of the second fibre type have substantially different, in particular average, finenesses. This can advantageously increase a tensile strength of the mat element, especially while keeping the weight per unit area low. The term “fineness” in this context is to be defined in particular in the Tex system (cf. DIN 60905-1:1985-12). The term “substantially different fineness” is intended to mean in particular finenesses whose Tex values (preferably expressed in the unit of measurement dtex) differ by at least a factor of 1.25, preferably by at least a factor of 1.5, advantageously by at least a factor of 2, particularly advantageously by at least a factor of 4, preferably by at least a factor of 8 and particularly preferably by at least a factor of 12. For example, the first type of fibre may comprise fibres having a fineness, in particular an average fineness, of 240 dtex and the second type of fibre may comprise fibres having a fineness, in particular an average fineness, of 30 dtex. In this case, the finenesses would differ by a factor of 8. In particular, it is conceivable that the fibres of the first fibre type have a fineness, in particular an average fineness, of at most 60 dtex, preferably at most 45 dtex, advantageously at most 30 dtex, preferably at most 20 dtex and particularly preferably at most 10 dtex. In particular, it is conceivable that the fibres of the second fibre type have a fineness, in particular an average fineness, of at least 150 dtex, preferably of at least 200 dtex, advantageously of at least 240 dtex, preferably of at least 300 dtex and particularly preferably of at least 350 dtex.

It is also proposed that the fibres of the fibre type with the higher fineness form friction fibres to increase the tensile strength of the mat element. In this way, the tensile strength of the mat element can be advantageously increased, in particular while keeping the weight per unit area low. Advantageously, the friction fibres with the high fineness have an increased total surface area, in particular friction surface area, in relation to the mass, whereby advantageously an increased frictional force can be generated, which in particular brings about the cohesion of the mat element. Advantageously, an improved stability of the mat element can be achieved. A higher fineness is to be understood in particular as a lower Tex value.

It is also proposed that the fibres of the first fibre type and the fibres of the second fibre type have substantially different, in particular average, lengths. In this way, high stability can advantageously be achieved with simultaneously high durability and/or high tensile strength. In particular, the fibres of the fibre type with the higher fineness are substantially longer than the fibres of the fibre type with the lower fineness. By “substantially different lengths” should be understood in particular lengths which differ by at least a factor of 1.25, preferably by at least a factor of 1.5, advantageously by at least a factor of 2, particularly advantageously by at least a factor of 3, preferably by at least a factor of 5 and particularly preferably by at least a factor of 10. In particular, the fibres of the fibre type with the higher fineness, in particular the fibres of the first fibre type, have a length, in particular an average length, of at least 2 cm, preferably at least 4 cm, advantageously at least 6 cm, particularly advantageously at least 9 cm, preferably at least 12 cm and particularly preferably at least 15 cm. In particular, the fibres of the fibre type with the lower fineness, in particular the fibres of the second fibre type, have a length, in particular an average length, of at most 15 cm, preferably at most 12 cm, advantageously at most 9 cm, particularly advantageously at most 6 cm, preferably at most 4 cm and particularly preferably at most 2 cm. In particular, the length of a fibre is measured in each case in a straightened state of the fibre.

If the fibres of the first fibre type have a first type and/or mixture of colour pigments which imparts a first colouring to the fibres of the first fibre type and if the fibres of the second fibre type have a second type and/or mixture of colour pigments which imparts a second colouring to the fibres of the second fibre type, which differs, in particular substantially, from the first colouring, an advantageous colour adaptation can be achieved in a particularly simple manner, which in particular permits an adjustment of a colouring of the mat element to different conditions at different installation locations.

If, in addition, the first colouring and the second colouring are intended to produce a camouflage effect in combination, an advantageous adaptation of the mat element to an environment of an installation site can be achieved. Thereby, an influence on and/or impairment of local fauna can be advantageously kept low. In particular, an impairment of a natural camouflage, especially a crypsis, of the indigenous fauna can be reduced. This can advantageously further increase environmental compatibility. Furthermore, an undesirable colour pollution of the environment, for example by partially rotten remains of a mat element, can be prevented. For example, the fibres of the first fibre type could have brown colour pigments and at the same time the fibres of the second fibre type could have green colour pigments. Alternatively, for example, the fibres of the first fibre type could have colour pigments of a first shade of a colour (e.g. dark green) and at the same time the fibres of the second fibre type of a second shade of the same colour (e.g. light green).

It is further proposed that at most 10% of the mat element, preferably at most 5%, in particular of the biodegradable fibres of the mat element, is biodegraded and/or disintegrated under controlled composting conditions, preferably in accordance with the standard DIN EN ISO 14855:2004-10, after a period of one year, preferably after a period of two years. Advantageously, a longer service life than that of natural fibres (coco, reed, jute, etc.) can thus be achieved with simultaneous complete biodegradability. Advantageously, a protective effect of the protective device can thereby be further improved. Preferably, the composting test is carried out under the composting conditions specified in the standard DIN EN ISO 14855:2004-10 and/or those listed below. In particular, the controlled composting conditions comprise mixing the biodegradable plastic fibres with an inoculum, which is preferably formed as a well aerated compost from an aerobic composting plant and is at least substantially free of larger inert objects. In particular, the biodegradable plastic fibres are comminuted in such a way that a total surface area of individual pieces of plastic fibres is smaller than 2 cm×2 cm. A proportion of total dry matter in the total inoculum of the composting experiment is in particular between 5:10 and 5.5:10. A proportion of organic dry matter in the total inoculum of the composting experiment is in particular less than 1.5:10. A proportion of organic dry matter in the total dry matter of the composting experiment is in particular less than 3:10. A pH of a mixture of one part inoculum and five parts deionised water is in particular between 7.0 and 9.0. An activity of the inoculum of the composting experiment is in particular such that a biodegradable reference material, for example a TLC cellulose reference film with a particle size smaller than 20 μm, outgasses within 10 days between 50 mg and 150 mg CO₂ per gram of organic dry matter. In particular, the mixture of inoculum and biodegradable plastic fibres is subjected to the composting test in a vessel of the test composting plant with an internal volume of at least 3 I, the vessel being at least two thirds filled with the mixture of inoculum and biodegradable plastic fibres. In particular, the filled vessel of the test composting unit is subjected to a constant temperature of 58° C.±2° C. and a water-saturated atmosphere at least substantially free of CO₂. The vessel of the test composting plant is shaken weekly during the composting experiment. A water content of the mixture of inoculum and the biodegradable plastic fibres is in particular at least substantially constant 50%. A pH value of the mixture of inoculum and the biodegradable plastic fibres is between 7.0 and 9.0, in particular during the entire composting experiment.

Furthermore, it is proposed that the protective device has a reinforcing element, in particular a net-like one, which is connected to the mat element. This can advantageously further increase a protective effect, in particular an erosion protection effect, of the protective device. The reinforcing element can in particular be formed from a plastic, in particular a biodegradable plastic, and/or a metal. In particular, the reinforcing element is spread out over an area. In particular, the reinforcing element is arranged and/or spread at least substantially parallel to the mat element. In particular, the reinforcing element and the mat element overlap at least to a large extent. In particular, the reinforcing element has a tensile strength which is substantially greater, in particular at least 10 times greater, preferably at least 100 times greater, preferably at least 500 times greater and particularly preferably at least 1000 times greater than the tensile strength of the mat element. In particular, the reinforcing element has an at least substantially regular structure. In particular, the mesh-like reinforcing element comprises regularly arranged and/or regularly shaped meshes. In particular, the mesh-like reinforcing element is braided, woven, welded or the like. In particular, the reinforcing element is formed of longitudinal elements which have a diameter, in particular an average diameter, which is at least 2 times, preferably at least 3 times, advantageously at least 4 times, preferably at least 5 times and particularly preferably at least 10 times greater than the diameter, in particular an average diameter, of the fibres of the composite, in particular of the fibres of the fibre type having the thickest fibres. The reinforcing element may be formed, for example, as a metal or plastic mesh or as a metal or plastic braid. The expression “joined” is intended to mean in particular frictionally joined, materially joined and/or preferably joined by a joining element, preferably by a seam. In particular, the reinforcing element is connected to the mat element in such a way that a movement of one of the two elements causes a movement of the other. In particular, a connection goes beyond simply placing the reinforcing element and the mat element on top of each other. However, it is also conceivable that the protective device is free of a reinforcing element.

It is also proposed that the reinforcing element is arranged above and/or below the mat element. This can advantageously further increase a protective effect, in particular an erosion protection effect, of the protective device. Preferably, the reinforcing element is arranged above the mat element. Preferably, in an assembly state, the mat element is arranged between the surface to be protected and the reinforcing element. Alternatively, however, it is also conceivable that the reinforcing element is integrated into the mat element and/or that the reinforcing element is braided around by the mat element.

In addition, it is proposed that the protective device comprises at least one connecting element which is intended to connect the mat element and the reinforcing element to each other. Advantageously, a reliable connection of the components of the protective device can thus be achieved. Advantageously, a protective effect of the protective device can thereby be further increased. In particular, the connecting element is made of a biocompatible material. Advantageously, this ensures a particularly high environmental compatibility. In particular, the connecting element is formed as a clip, a staple or one or more threads, for example a seam, a loop and/or a knot. In particular, the connecting element may be designed to be flexurally rigid or flexurally slack. Preferably, the protective device comprises a plurality of connecting elements which are distributed in particular at regular or irregular intervals over a surface extension of the protective device. In particular, the connecting element is provided for a relatively loose connection of the mat element and the reinforcing element. Preferably, the connecting element allows play, in particular movement, of the mat element relative to the reinforcing element in the direction of the reinforcing element. In particular, the mat element is at least partially spaced apart from the reinforcing element in a state fastened to the reinforcing element by the connecting element. In particular, the mat element is suspended from the reinforcing element by the connecting element at a distance which is in particular at least 1 cm, preferably at least 2 cm, advantageously at least 3 cm, preferably at least 4 cm and particularly preferably at least 5 cm. In particular, the mat element is free of contact with the reinforcing element in a state in which it is attached to the reinforcing element by the connecting element and in which the mat element hangs freely below the reinforcing element. In this way, it can be advantageously achieved that the mat element, after installation, can lie as freely and/or as closely as possible against the surface to be protected, in particular even if the surface to be protected is uneven.

If, in addition, the connecting element is designed to be biodegradable, a particularly high level of environmental compatibility can be advantageously ensured. For example, the connecting element can be made at least partially or completely from a PLA plastic. Preferably, however, the connecting element is formed from a different material than the mat element. It is conceivable that the connecting element has a comparable, a higher or a lower service life under identical environmental conditions as/than the mat element. Preferably, the connecting element has a substantially lower service life than the mat element. Preferably, a connection between the mat element and the reinforcing element created by the connecting element will loosen within a few days, within a few weeks or within a few months when exposed to the weather.

It is further proposed that the connecting element is designed to dissolve when exposed to weather, in particular water (e.g. rainwater) and/or sunlight (e.g. UV radiation). Advantageously, this can further improve a protective effect of the protective device. In particular, the mat element advantageously separates from the reinforcing element after installation on the surface to be protected, whereby a particularly close fit of the mat element on the surface and, at the same time, simple installation can be ensured by means of the easily laid, stiffer and more stable reinforcing element. Advantageously, a high erosion protection effect can be achieved by the mat element resting directly and closely on the surface. At the same time, additional stone chip protection or the like can advantageously be achieved by the stable reinforcing element stretched over the surface. In particular, the connecting element is made of a water-soluble and/or UV-decomposable material, especially plastic. For example, the connecting element may be formed as a polyvinyl alcohol (PVA) thread. In particular, it is conceivable that the connecting element is deliberately sprayed with water after completion of the installation of the protective device on a surface in order to accelerate and/or cause the detachment of the mat element from the reinforcing element.

If the reinforcing element is sewn to the mat element, in particular with the connecting element, a simple, in particular easily producible, and reliable connection between the mat element and the reinforcing element can advantageously be achieved.

If, in addition, the reinforcing element is designed as a wire mesh, a particularly high stability of the protective device and thus a particularly high protective effect can advantageously be achieved. Advantageously, the protective device with the wire mesh has a high strength and/or stability. Advantageously, the wire mesh is intended to retain the soil and/or rock of the terrain to be protected. In this way, a high level of safety can advantageously be achieved. In particular, the wire mesh has a regular mesh shape. Alternatively, the mesh shape of individual meshes may deviate from other meshes and/or the wire mesh may have an irregular mesh shape. In particular, the wire mesh has a rhomboid mesh shape, especially a regular one. This means that even smaller lumps of rock can be safely stopped. Alternatively, the wire mesh can also have another mesh shape, for example a square mesh shape, a hexagonal mesh shape and/or a round mesh shape. In particular, the wire of the wire mesh has a thickness of, for example, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm or even more or even less or also a diameter of an intermediate value. Larger, in particular considerably larger, diameters are further conceivable if the longitudinal element comprises several components, in particular several wires, as for example in the case of a wire rope or a strand or a wire bundle or the like. In particular, the wire of the wire mesh has a corrosion protection layer, for example a zinc layer applied by means of a hot-dip galvanising process, an Al/Zn corrosion protection layer, an Al/Zn/Mg corrosion protection layer or the like. Alternatively, the wire is made of stainless steel and/or stainless steel. In particular, the corrosion protection layer has a mass per unit area of at least 110 g/m², preferably at least 150 g/m², preferably at least 200 g/m² and particularly preferably at least 250 g/m². In particular, the wire mesh is formed in a planar manner. Preferably, the wire mesh extends at least over a major part of a planar overall extension of the protective device, in particular of the mat element. Preferably, the wire mesh extends completely over the entire surface of the protective device, in particular of the mat element.

It is also proposed that the wire mesh is formed at least from interwoven helical longitudinal elements. In this way, an advantageously structured wire mesh can be produced. Advantageously, such a wire mesh has a high tensile strength. Advantageously, such a wire mesh is designed to be rollable with the protective device, in particular the tangled fabric or the fleece-like structure. This can advantageously facilitate assembly and/or transport. In particular, a longitudinal element has a longitudinal extension which is at least 10 times, preferably at least 50 times and preferably at least 100 times as large as a maximum transverse extension extending perpendicularly to the longitudinal extension. In particular, at least one of the helical longitudinal elements, preferably all of the helical longitudinal elements, is made at least of a single wire, a wire bundle, a wire strand, a wire rope and/or another longitudinal element comprising at least one wire. In particular, the longitudinal elements have a shape of a flat, in particular flattened, spiral. The helical longitudinal elements have in particular at least one first leg, at least one second leg and at least one bending point connecting the first leg and the second leg to one another. Advantageously, adjacent interwoven helical longitudinal elements are connected via their bending points. Particularly advantageously, two bending points of different helical longitudinal elements are connected to each other, in particular hooked into each other. In particular, the helical longitudinal elements of the wire mesh have the same direction of rotation. Advantageously, in each case two helical longitudinal elements are knotted to one another, in particular in each case at a first of their ends and/or in each case at a second of their ends opposite the first ends.

If the wire mesh comprises at least one wire which is formed at least partially from a high-strength steel, in particular with a tensile strength of at least 500 N/mm², preferably at least 750 N/mm², advantageously at least 1000 N/mm², particularly advantageously at least 1770 N/mm², preferably at least 2500 N/mm² and particularly preferably at most 3000 N/mm², a particularly high stability of the protective device can advantageously be achieved, preferably nevertheless with the lowest possible weight. In particular, a high level of safety can be achieved.

It is also proposed that the wire mesh has a three-dimensional, mattress-like structure. This makes it advantageous to achieve a high flexibility of the protective device, in particular of the wire mesh, in relation to a load in a load direction perpendicular to the main extension plane of the wire mesh. For example, the protective device can thereby advantageously be walked on and/or driven over to a limited extent, in particular during assembly. A “mattress-like structure” is to be understood in particular as a three-dimensional planar structure which has a springing capacity in a direction perpendicular to the planar extension of the structure.

Furthermore, slope protection with the protective device is proposed. This can advantageously provide slope protection with a high level of environmental compatibility.

In addition, it is proposed to use the protective device for re-vegetation and/or re-vegetation of a surface, in particular a sloping and/or erosion-prone surface. In particular, this enables efficient re-vegetation, in particular through advantageous germination conditions and/or advantageous prevention of the washing out of dispersed seeds during heavy rainfall. In addition, a use as an erosion control mat for an unvegetated sloping surface, a use as a drainage mat in or on a floor or on a building roof and/or a use for a protection of agricultural products, for example fruits, directly at a cultivation site is proposed.

Furthermore, a method for manufacturing the protective device, in particular the erosion protection device and/or the drainage device, preferably the geotextile, is proposed, in which a mat element, which is at least intended to be spread flat over a surface to be protected, is manufactured as a, in particular three-dimensional, fleece-like, in particular tangled fleece-like, composite of a plurality of biodegradable plastic fibres. In this way, a protective device with the above-mentioned advantageous properties can be produced.

Furthermore, it is proposed that the biodegradable plastic fibres are stretched, in particular pre-stretched, prior to the production of the non-woven composite. This can advantageously further improve the protective properties of the protective device. In addition, a durability, in particular service life, can thereby advantageously be increased. Furthermore, a tensile strength of the fibres can be advantageously increased.

Furthermore, it is proposed that the biodegradable plastic fibres are preformed, in particular pre-crimped, before the fleece-like composite is produced. This can advantageously further improve the protective properties of the protective device. Advantageously, an improved cohesion of the composite can be achieved, in particular by higher frictional forces and/or a higher degree of entanglement. Advantageously, an increased tensile strength of the mat element can thus be achieved.

It is also proposed that the mat element is connected, in particular sewn, to a reinforcing element, in particular a net-like reinforcing element. In this way, a simple, in particular easily producible, and reliable connection between the mat element and the reinforcing element can be advantageously achieved.

Furthermore, a method is proposed for an installation of the protective device, in particular the erosion protection device and/or the drainage device, preferably the geotextile, wherein the mat element connected to the reinforcing element by a connecting element is installed on the surface to be protected in such a way that the mat element is arranged between the surface to be protected and the reinforcing element, and wherein the connecting element is dissolved by weathering after installation has taken place, so that the mat element is separated from the reinforcing element and lies as closely as possible over the surface to be protected. Advantageously, a high erosion protection effect can be achieved by the mat element lying directly and closely on the surface. At the same time, additional stone chip protection or the like can advantageously be achieved by the stable reinforcement element stretched over the surface.

The protective device according to the invention, the slope protection device according to the invention and/or the methods according to the invention are not intended here to be limited to the application and embodiment described above. In particular, the protective device according to the invention, the slope protection device according to the invention and/or the methods according to the invention may have a number of individual elements, components, process steps and units deviating from a number mentioned herein in order to fulfil a mode of operation described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages can be seen in the following description of the drawings. Two embodiments of the invention are shown in the drawings. The drawings, the description and the claims contain numerous features in combination. The skilled person will expediently also consider the features individually and combine them to form useful further combinations. They show:

FIG. 1 a is a schematic lateral section through a slope protection with a protection device and a proposed use of the protection device;

FIG. 1 b is a schematic representation of an alternative use of the protective device;

FIG. 2 is a schematic top view of a mat element of the protective device;

FIG. 3 is a schematic side view of the mat element;

FIG. 4 is an enlarged detailed view of a section of the mat element;

FIG. 5 is a schematic representation of fibres of different fibre types of the mat element;

FIG. 6 is a schematic flow diagram of a process for manufacturing the protective device;

FIG. 7 is a schematic illustration of a stretching effect on one of the fibres;

FIG. 8 is a schematic top view of an alternative protective device with a mat element and with a reinforcing element;

FIG. 9 is a schematic side view of the alternative protective device;

FIG. 10 is a flow diagram of a process for manufacturing the alternative protective device;

FIG. 11 is a schematic representation of a manufacturing device for producing the alternative protective device;

FIG. 12 is a schematic lateral section through an embankment protection with the alternative protection device immediately after installation of the embankment protection;

FIG. 13 is a flowchart of a method for assembling the alternative protective device; and

FIG. 14 is the schematic lateral section through the slope protection after weathering.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 a shows a lateral section through an embankment protection 32 a and the underlying soil and/or rock. The slope protection 32 a is intended to protect a slope against erosion. The slope protection 32 a is provided for securing the slope against landslides and/or washing out of slope material. Alternatively or additionally, the slope protection 32 a can also be provided for drainage. The slope protection 32 a comprises a protection device 34 a. The protection device 34 a is configured as an erosion protection device. Alternatively or additionally, the protective device 34 a may also be designed as a drainage device. The protective device 34 a is formed as a geotextile. The protective device 34 a comprises a mat element 10 a. The protective device 34 a, in particular at least the mat element 10 a, is intended to be spread flat over a surface 12 a to be protected. The protective device 34 a, in particular at least the mat element 10 a, is intended to cover a surface 12 a of the slope in a planar manner. The protective device 34 a, in particular at least the mat element 10 a, is designed in the form of a web and can be rolled up for transport. To cover the surface 12 a to be protected, strips of the protective device 34 a, in particular at least the mat element 10 a, are unrolled on the surface 12 a, joined together at the side edges of individual strips and spread out and fastened on the surface 12 a to be protected by means of tensioning ropes and anchoring elements 36 a. FIG. 1 a shows a use of the protective device 34 a, in particular of the mat element 10 a during a re-vegetation and/or a re-vegetation of the surface 12 a. Use as an erosion control mat for ungreened sloping surfaces or as a drainage mat in or on a soil is also conceivable. FIG. 1B shows an alternative use of a protective device 34′a to protect agricultural products, in this case fruits 72 a, in which the protective device 34′a is placed directly at a cultivation site between the fruits 72 a and the soil, so that the fruits 72 a do not rest directly on the moist and/or dirty soil.

FIG. 2 shows a schematic top view of the mat element 10 a. The exemplary mat element 10 a shown in FIG. 2 has a basis weight of less than 400 g/m². The mat element 10 a comprises a plurality of fibres 16 a. The plurality of fibres 16 a forms a composite 14 a. The composite 14 a with the plurality of fibres 16 a is three-dimensionally extended (cf. FIG. 3 ). The composite 14 a with the plurality of fibres 16 a has a thickness 38 a. The exemplary thickness 38 a shown in FIG. 3 is about 4 cm. The composite 14 a with the plurality of fibres 16 a is fleece-like. The composite 14 a with the plurality of fibres 16 a forms a non-woven fabric. The composite 14 a with the plurality of fibres 16 a is tangled nonwoven. The composite 14 a with the plurality of fibres 16 a forms a random layer nonwoven fabric. The mat element 10 a is formed from the non-woven composite 14 a of the plurality of fibres 16 a.

The fibres 16 a of the composite 14 a are formed as biodegradable fibres 16 a. The fibres 16 a of the composite 14 a are formed as plastic fibres 16 a. The fibres 16 a of the composite 14 a are formed as biodegradable plastic fibres 16 a. The biodegradation of the biodegradable plastic fibres 16 a proceeds more slowly than a biodegradation of natural fibres such as reed fibres, jute fibres or coconut fibres. At most 10% of the mat element 10 a, in particular the fibres 16 a, is/are biodegraded and/or disintegrated under controlled composting conditions (according to DIN EN ISO 14855:2004-10) within a period of one year. The fibres 16 a of the composite 14 a comprise a biodegradable polylactide plastic (PLA). The fibres 16 a of the composite 14 a comprise the biodegradable PLA plastic. The fibres 16 a of the composite 14 a have a specific gravity greater than the specific gravity of water. The fibres 16 a of the composite 14 a are stretched. The fibres 16 a of the composite 14 a are pre-stretched. The fibres 16 a of the composite 14 a have selectively admixed colour pigments (not shown). The colour pigments are biocompatible. The colour pigments are biodegradable.

FIG. 4 shows a detailed view of a section of the mat element 10 a. The fibres 16 a of the composite 14 a forming the mat element 10 a comprise a first fibre type 18 a with a portion of all fibres 16 a (cf. FIG. 5 ). The fibres 16 a of the composite 14 a forming the mat element 10 a comprise a second fibre type 40 a comprising a further portion of all the fibres 16 a (cf. FIG. 5 ). The fibres 16 a of the first fibre type 18 a and the fibres 16 a of the second fibre type 40 a are substantially different. The fibres 16 a of the first fibre type 18 a and the fibres 16 a of the second fibre type 40 a have substantially different finenesses. The fibres 16 a of the higher fineness fibre type 18 a, 40 a form friction fibres for increasing a tensile strength of the mat element 10 a. The fibres 16 a of the first fibre type 18 a have a substantially higher fineness. In the case shown, the fibres 16 a of the first fibre type 18 a form the friction fibres.

In FIG. 5 , one fibre 16 a of the first fibre type 18 a and one fibre 16 a of the second fibre type 40 a are shown as examples. The fibres 16 a of the composite 14 a are preformed. The fibres 16 a of the composite 14 a are pre-corrugated. The fibres 16 a have an average length 20 a, 42 a of at most 20 cm. The fibres 16 a of the first fibre type 18 a and the fibres 16 a of the second fibre type 40 a have substantially different average lengths 20 a, 42 a. In the exemplary case shown in FIG. 5 , the fibres 16 a of the first fibre type 18 a have an average length 20 a of 15 cm. In the exemplary case shown in FIG. 5 , the fibres 16 a of the second fibre type 40 a have an average length 42 a of 7 cm. The fibres 16 a of the composite 14 a have an average diameter 22 a, 44 a of less than 2 mm. In the case exemplified in FIG. 5 , the fibres 16 a of the first fibre type 18 a have an average diameter 22 a of about 0.2 mm. The fibres 16 a of the first fibre type 18 a thus form the friction fibres. In the exemplary case shown in FIG. 5 , the fibres 16 a of the second fibre type 40 a have an average diameter 44 a of about 1 mm. The fibres 16 a of the first fibre type 18 a have a first type and/or mixture of colour pigments, which imparts a first colouration (indicated by a first hatching) to the fibres 16 a of the first fibre type 18 a. The fibres 16 a of the second fibre type 40 a comprise a second type and/or mixture of colour pigments which imparts a second colouration (indicated by a second hatching) to the fibres 16 a of the second fibre type 40 a. The first colouring is substantially different from the second colouring. The first colouring is exemplarily a shade of brown. The second colouring is exemplarily a shade of green. The different first and second colourings are intended to combine to create a camouflage effect.

FIG. 6 shows a flow diagram of a process for manufacturing the protective device 34 a, in which the mat element 10 a is manufactured as the non-woven composite 14 a from the plurality of biodegradable plastic fibres 16 a. In at least one process step 46 a, the fibres 16 a, in particular the fibres 16 a of both fibre types 18 a, 40 a, are produced from the biodegradable plastic (e.g. PLA), preferably spun and/or extruded. In at least one further process step 48 a, the biodegradable plastic fibres 16 a are stretched. In the process step 48 a, the fibres 16 a are stretched prior to the production of the non-woven composite 14 a. During the stretching of the fibres 16 a, polymer chains in the interior of the fibres 16 a partially align, resulting in a partial crystallisation of the fibre material, in particular an increase in a partially crystallised portion of the fibre material and thus in a reinforcement of the fibres 16 a (cf. also the illustration of the stretching in FIG. 7 ). In at least one further optional process step 50 a, the biodegradable plastic fibres 16 a are deformed and/or corrugated. In the process step 50 a, the fibres 16 a are pre-deformed and/or pre-crimped prior to forming the non-woven composite 14 a. In at least one further process step 52 a, the biodegradable plastic fibres 16 a are cut to defined lengths 20 a, 42 a. In at least one further process step 54 a, the fibres 16 a, in particular the fibres 16 a of the two fibre types 18 a, 40 a, are used to produce the nonwoven-like composite 14 a, in particular the nonwoven fabric. The nonwoven-like composite 14 a, in particular the nonwoven fabric, is produced in the process step 54 a, for example, by needling. Alternatively or additionally, other known (mechanical, chemical and thermal) processes for producing the nonwoven fabric from the fibres 16 a are also conceivable (e.g. calendering, hydroentanglement, sewing knitting, etc.).

FIG. 7 illustrates the stretching effect. In the upper drawing of FIG. 7 , an unstretched fibre 16 a is shown, the polymer chains of which are substantially disordered and/or undirected. In the lower drawing of FIG. 7 , a drawn fibre 16 a is shown, the polymer chains of which are substantially straightened and/or directed. By straightening the polymer chains, an increase in a partially crystallised portion of the fibres 16 a and thus a strengthening of the fibre 16 a can be achieved.

FIGS. 8 to 14 show a further embodiment of the invention. The following descriptions and the drawings are essentially limited to the differences between the embodiment examples, whereby reference can in principle also be made to the drawings and/or the description of the other embodiment examples, in particular of FIGS. 1 to 7 , with regard to components with the same designation, in particular with regard to components with the same reference signs. To distinguish the embodiment examples, the letter a is placed after the reference signs of the embodiment example in FIGS. 1 to 7 . In the embodiments of FIGS. 8 to 14 , the letter a is replaced by the letter b.

FIG. 8 shows a top view of an alternative guard 34 b. The alternative protective device 34 b comprises a mat member 10 b. The mat member 10 b is formed from a non-woven composite 14 b having a plurality of fibres 16 b, wherein the fibres 16 b are formed as biodegradable plastic fibres 16 b. The alternative protective device 34 b includes a reinforcing member 24 b. The reinforcing element 24 b is formed in a net-like shape. The reinforcing element 24 b is arranged above the mat element 10 b. The reinforcing element 24 b is formed as a wire mesh 28 b. The wire mesh 28 b comprises a wire 30 b formed entirely of a high-strength steel. The wire mesh 28 b has a three-dimensional mattress-like structure. The wire mesh 28 b is formed of flat coils twisted into each other, which form diamond-shaped or square meshes.

FIG. 9 shows a side view of the alternative protective device 34 b with the reinforcing element 24 b. The reinforcement element 24 b is connected to the mat element 10 b. The reinforcing member 24 b is sewn to the mat member 10 b. The alternative protective device 34 b comprises a connecting element 26 b. The alternative protective device 34 b comprises a plurality of at least substantially identical connecting elements 26 b. The connecting element 26 b is provided for connecting the mat element 10 b and the reinforcing element 24 b to each other. The reinforcing element 24 b is sewn to the mat element 10 b by means of the connecting element 26 b. In a horizontal orientation, as exemplarily shown in FIG. 9 , the mat element 10 b hangs on the connecting elements 26 b below the reinforcing element 24 b. In this case, the mat element 10 b and the reinforcing element 24 b do not touch. In this case, the mat element 10 b and the reinforcing element 24 b are spaced apart from each other. The connecting element 26 b is biodegradable. The connecting element 26 b is formed to be biocompatible. The connecting element 26 b is adapted to dissolve upon exposure to weather. The mat element 10 b is adapted to disengage from the reinforcing element 24 b after disintegration of the connecting element 26 b. The mat member 10 b is adapted to spread snugly over a surface 12 b to be protected after disengagement from the reinforcing member 24 b.

FIG. 10 shows a flow diagram of a method of manufacturing the alternative protective device 34 b. In at least one process step 56 b, the mat element 10 b is manufactured as described in the process disclosed in connection with FIG. 6 . In at least one further process step 58 b, the mat element 10 b is joined to the reinforcing element 24 b. In the method step 58 b, the mat element 10 b is sewn to the reinforcing element 24 b. In step 58 b, the mat element 10 b is sewn to the reinforcement element 24 b.

FIG. 11 shows a substantially simplified schematic representation of a manufacturing device 60 b for manufacturing the alternative protective device 34 b. The manufacturing device 60 b is designed as a kind of sewing machine. The manufacturing device 60 b comprises an unrolling device 62 b with a rolled-up mat element 10 b and an unrolling device 64 b with a rolled-up reinforcing element 24 b. The mat member 10 b and the reinforcing member 24 b are unrolled in a synchronised manner from the unrolling devices 62 b, 64 b and fed to a sewing device 66 b of the manufacturing device 60 b. The sewing device 66 b is provided for sewing the mat element 10 b and the reinforcing element 24 b together, in particular by means of the connecting element 26 b.

FIG. 12 shows a lateral section through an alternative slope protection 32 b with the alternative protection device 34 b, comparable to FIG. 1 a , immediately after mounting the alternative protection device 34 b on the surface 12 b. The mat element 10 b is still connected to the reinforcing element 24 b by means of the connecting element 26 b.

FIG. 13 shows a flow diagram of a method for mounting the alternative protective device 34 b. In at least one process step 68 b, the mat element 10 b connected to the reinforcing element 24 b by the connecting element 26 b is installed on the surface 12 b to be protected by means of anchoring elements 36 b. The alternative protection device 34 b is installed in the process step 68 b so that the mat element 10 b is arranged between the surface 12 b to be protected and the reinforcement element 24 b. In at least one process step 70 b, which may in particular be carried out autonomously by rainfall or the like or provoked, the connecting element 26 b is dissolved by water and/or UV radiation after installation has been carried out. In the process step 70 b, the mat element 10 b is separated from the reinforcing element 24 b and sinks downwards. In most common installation positions, this will cause the mat element 10 b to self-fit as closely as possible over the surface 12 b to be protected.

FIG. 14 shows the lateral section through an alternative slope protection 32 b shown in FIG. 12 after the connecting elements 26 b have been disconnected. The mat element 10 b is no longer connected to the reinforcing element 24 b. The mat element 10 b rests on the surface 12 b. The flexible mat element 10 b nestles against the surface 12 b. In the state shown in FIG. 14 , the mat element 10 b develops its maximum erosion protection effect, while the reinforcement element 24 b mainly serves to protect against rockfall and/or major landslides. 

1-32. (canceled)
 33. A protective device for erosion protection and/or drainage comprising a mat element which is intended to be spread flat over a surface to be protected and which is formed at least to a large extent from a three-dimensional, nonwoven-like, and tangled nonwoven-like composite having a multiplicity of fibres, wherein the fibres are formed as biodegradable plastic fibres.
 34. The protective device according to claim 33, wherein the fibres comprise a biodegradable polylactide plastic (PLA).
 35. The protective device according to claim 33, wherein at least a substantial part of all fibres of the composite are stretched and/or pre-stretched.
 36. The protective device according to claim 33, wherein at least a substantial part of all fibres of the composite are preformed and/or precorrugated.
 37. The protective device according to claim 33, wherein the mat element has a weight per unit area of less than 400 g/m².
 38. The protective device according to claim 33, wherein at least a substantial part of all fibres has a specific gravity greater than the specific gravity of water.
 39. The protective device according to claim 33, wherein the fibres have an average length of at most 20 cm.
 40. The protective device according to claim 33, wherein at least a substantial part of the fibres of the composite has specifically admixed colour pigments which are biocompatible and/or biodegradable.
 41. The protective device according to claim 33, wherein at least a substantial part of all fibres forming the composite have a diameter of less than 2 mm.
 42. The protective device according to claim 33, wherein the fibres comprise at least a plurality of fibres of a first fibre type and at least a plurality of fibres of a second fibre type, said fibres of said first fibre type and said second fibre type being substantially different from each other.
 43. The protective device according to claim 42, wherein the fibres of the first fibre type and the fibres of the second fibre type have substantially different finenesses.
 44. The protective device according to claim 43, wherein the fibres of the fibre type with the higher fineness form friction fibres for increasing a tensile strength of the mat element.
 45. The protective device according to claim 42, wherein the fibres of the first fibre type and the fibres of the second fibre type have substantially different average lengths.
 46. The protective device according to claim 42, wherein the fibres of the first type of fibres comprise a first type and/or mixture of colour pigments which imparts a first colouring to the fibres of the first fibre type, and in that the fibres of the second fibre type comprise a second type and/or mixture of colour pigments which imparts to the fibres of the second fibre type a second colouring which is different from the first colouring.
 47. The protective device according to claim 46, wherein the first colouring and the second colouring are intended to produce a camouflage effect in combination.
 48. The protective device according to claim 33, wherein at most 10% of the mat element is biodegraded and/or disintegrated under controlled composting conditions after a period of one year.
 49. The protective device according to claim 33, wherein a reinforcing element is connected to the mat element.
 50. The protective device according to claim 49, wherein the reinforcing element is arranged above and/or below the mat element.
 51. The protective device according to claim 49, wherein at least one connecting element is provided to connect the mat element and the reinforcing element together.
 52. The protective device according to claim 49, wherein the connecting element is biodegradable or is adapted to disintegrate upon exposure to weather.
 53. The protective device according to claim 49, wherein the reinforcing element is sewn to the mat element.
 54. The protective device according to claim 49, wherein the reinforcing element is formed as a wire mesh.
 55. The protective device according to claim 54, wherein the wire mesh comprises at least one wire which is at least partially formed from a high strength steel.
 56. The protective device according to claim 49, wherein the reinforcing element has a three-dimensional, mattress-like structure.
 57. A slope protection comprising the protective device according to claim
 33. 58. The use of the protective device according to claim 33 in any of: a new greening and/or a re-greening of a surface; a sloping surface; a surface at risk of erosion; as a drainage mat in or on a floor or on a building roof; or for a protection of agricultural products directly at a cultivation site.
 59. A method of manufacturing a protective device for erosion protection and/or drainage, wherein the method comprises the step of producing a three-dimensional, nonwoven-like, and tangled nonwoven-like composite from a plurality of biodegradable plastic fibres adapted to be spread out flat over a surface to be protected.
 60. The method according to claim 58, further comprising the step of stretching the biodegradable plastic fibres prior to the production of the nonwoven-like composite or pre-corrrugating the biodegradable plastic fibres before the nonwoven-like composite is produced.
 61. The method according to claim 58, further comprising the step of connecting the mat element to a reinforcing element.
 62. A method for the installation of a protective device for erosion protection device and/or drainage, comprising the steps of: forming a mat element which is intended to be spread flat over a surface to be protected and which is formed at least to a large extent from a three-dimensional, nonwoven-like, and tangled nonwoven-like composite having a multiplicity of fibres, wherein the fibres are formed as biodegradable plastic fibres; connecting the mat element to a reinforcing element by a connecting element; and installing the mat element and reinforcing element on a surface to be protected such that the mat element is arranged between the surface to be protected and the reinforcing element; wherein the connecting element is dissolved by weathering after installation has taken place, so that the mat element is separated from the reinforcing element and lies over the surface to be protected. 